SIGMAKOKI Internal reflection type parabolic lens

An internal reflection parabolic lens is an optical element that can collect light incident from various directions on the output end surface by reflecting it on the streamlined side surface. It is used as a solar cell concentrator. If the incident angle is 25° or less and the parallel light is incident from any direction, the light can be efficiently collected on the output end surface. Since it uses internal reflection of glass, the configuration can be simplified compared to a lens system. By using press molding technology for glass lenses, both high performance and low price are achieved. *Since total reflection is caused by the side surface (aspheric surface), if the side surface gets fingerprints or dirt, the reflectivity will be extremely poor. *The reflectivity of the side surface is 99% or more, but since the input and output surfaces are not anti-reflective coated, a reflection loss of about 4% occurs on each surface. *The light emitted from the end surface does not concentrate on one point, but diverges widely and randomly. *For this reason, it cannot be used for focusing beams or collimated beams.